| xPC Target | |
The DM6804 has one AM9513A chip with 5 counters.
The DM6804 PWM driver programs the AM9513A for PWM (Pulse Width Modulation) signal generation (a square wave with fixed frequency and variable duty cycle). The block has one input which defines the variable duty cycle between 0 and 1. For the corresponding counter channel, the PWM signal is output at the pin named OUT.
Scaling Input to Output
| Hardware Output |
Block Input Data Type |
Scaling |
| TTL |
double |
0 to 1 |
Driver Block Parameters
Counter -- From the list, choose 1, 2, 3, 4, or 5 to select which counter is used with this driver block. In each case, one block is needed for each counter.
Frequency base -- From the list, choose F1=5MHz, F2=500kHz, F3=50kHz, F4=5kHz, or F5=500Hz to set the base frequency.
Relative output frequency -- Enter a value between 0 and 1. The Relative output frequency is multiplied by the Frequency base to set the fixed output frequency of the PWM-signal.
For example, if the output frequency of a square wave has to be 17.5 kHz, then choose F2=500kHz as the Frequency Base and enter 0.175 as the Relative Output Frequency. 500kHz x 0.175 = 87.5 kHz
Level sequence of square wave -- From the list, choose either high-low or low-high.
high-low, the square wave period starts with the TTL high part followed by the TTL low part.
low-high, the square wave period starts with the TTL low part followed by the TTL high part.
In either case, the duty cycle entering the block defines the duration of the TTL high part.
Level when disarmed -- From the list, choose either high or low. The counter is automatically disarmed when the target application is not running and gets armed when the application begins running. This parameter sets the TTL level when the counter is disarmed.
Sample time -- Enter the base sample time or a multiple of the base sample time. The sample time indicates the update rate of registration on the input (Duty Cycle)
Base address --Enter the base address of the board. This entry must corresponds to the DIP-switch settings on the board. For example, if the base address is 300 (hexadecimal), enter
| | DM6804 Digital Output | DM6804 Counter PWM & ARM | |